ProRes in 4K limited to iPhone 13 models with 256GB of storage or more
Support for Apple's ProRes video compression format is a tentpole feature for iPhone 13 Pro, but its headlining capability -- 4K video recording at 30 frames per second -- is limited to models with storage allotments of 256GB or more.

Apple made a point of highlighting iPhone 13 Pro's ProRes codec handling during Tuesday's unveiling, positioning the technology as a "pro" feature exclusive to its most expensive handsets.
ProRes offers high color fidelity and image quality with relatively low storage overhead, an ideal combination for mobile filmmaking. The codec also benefits from fairly wide adoption in existing post-production workflows and can be exported to programs like Final Cut Pro.
According to Apple's iPhone 13 Pro specifications, ProRes in 4K at 30fps is limited to 256GB, 512GB and 1TB models. The 128GB handset variant can shoot ProRes at 30fps, but at a significantly reduced resolution of 1080p.
Apple does not explain the limitation, but it can be assumed that the 128GB option does not provide the data transfer speeds necessary to keep up with 4K video creation.
ProRes is not slated to debut with iPhone 13 Pro when the device line hits stores next week and will instead roll out in an update due to arrive later this fall. Apple has a track record of staggering the release of its advanced camera technologies, with past years seeing ProRAW, Deep Fusion and Portrait Mode come to iPhone in iOS updates.
In addition to ProRes, iPhone 13 Pro features a number of camera hardware and software improvements like optical image stabilization on the new 3x telephoto lens, a new ultra-wide module with macro functionality, a new Cinematic mode, Night Mode across all cameras and more.
Read on AppleInsider

Apple made a point of highlighting iPhone 13 Pro's ProRes codec handling during Tuesday's unveiling, positioning the technology as a "pro" feature exclusive to its most expensive handsets.
ProRes offers high color fidelity and image quality with relatively low storage overhead, an ideal combination for mobile filmmaking. The codec also benefits from fairly wide adoption in existing post-production workflows and can be exported to programs like Final Cut Pro.
According to Apple's iPhone 13 Pro specifications, ProRes in 4K at 30fps is limited to 256GB, 512GB and 1TB models. The 128GB handset variant can shoot ProRes at 30fps, but at a significantly reduced resolution of 1080p.
Apple does not explain the limitation, but it can be assumed that the 128GB option does not provide the data transfer speeds necessary to keep up with 4K video creation.
ProRes is not slated to debut with iPhone 13 Pro when the device line hits stores next week and will instead roll out in an update due to arrive later this fall. Apple has a track record of staggering the release of its advanced camera technologies, with past years seeing ProRAW, Deep Fusion and Portrait Mode come to iPhone in iOS updates.
In addition to ProRes, iPhone 13 Pro features a number of camera hardware and software improvements like optical image stabilization on the new 3x telephoto lens, a new ultra-wide module with macro functionality, a new Cinematic mode, Night Mode across all cameras and more.
Read on AppleInsider
Comments
A minute of 4K ProRes 4444HQ is 8GB
Whichever flavor of ProRes it is, it's gonna suck up storage really quickly. The only other possible reason is the storage in the 128 isn't fast enough to keep up, but that seems unlikely.
My guess, is the 128 version is for the typical user and has a lower spec, read: slower less expensive RAM.
However, it would be great if it was 422 on the iPhone to save some space but still give you a better file format to import into an NLE for use on documentaries, weddings, home movies and such.
https://pbs.twimg.com/media/E_1Z5cvVEAMzHfn?format=jpg&name=large
https://www.dpreview.com/news/0999511934/report-prores-recording-apple-new-iphone-13-6gb-4gb
A 128GB model can give over an hour of HDR 1080p video, which is fine for short clips and movie makers can offload them ( https://www.diyvideostudio.com/how-to-manage-iphone-storage/ ).
Quality-wise, 1080p 10-bit video 147Mb/s is really good quality footage. Video content like Youtube, documentaries and adult films make up a huge volume of produced content and this will work great for their workflows. Obviously the highest end movies and commercials will continue to use the highest-end cameras available but film makers like Steven Soderberg put out mainstream movies using an iPhone 8 shooting at 4k. The new models with HDR, better low light performance and higher bitrate will continue to close the gap between consumer level and pro level camera hardware.